TAMPA, Florida -- Fred Turner's ex-wife, who's among his closest family, says he was a reserved, quiet guy who used to live in Clearwater, and she can't imagine anyone wanting to hurt him.

She told 10 News off-camera she hopes someone will come forward with information leading to the 47-year-old's killer.

On Saturday, Turner was in Tampa for unknown reasons and driving back to Orlando, where he's lived for the last five years and worked as a housekeeping director.

As he neared 50th Street and Columbus Drive, near an entrance ramp to I-4, Turner called police to alert them that a driver had flashed a handgun and was following him.

He headed east on I-4, and as he approached the highway's intersection with I-75, the Hillsborough County Sheriff's Office says someone in the other car fired shots at him. Witnesses report Turner immediately pulling over. Deputies found him dead in his car with no suspect in sight.

The person or people of interest may be driving a gray, newer model Ford Taurus with tinted windows.

"I don't know why anyone would do that. I mean, he was a nice guy. I don't see him having any enemies," said a neighbor of Turner's in Orlando, who wanted to remain anonymous. "He stayed to himself. He was a quiet guy. I just can't believe that someone would just openly, randomly shoot him on I-4. That's horrible."

Investigators are piecing together 911 calls, but a missing piece of the puzzle is tips from drivers who may have been in the area around 3 p.m. on Saturday.

If you have any information, call the Hillsborough County Sheriff's Office at 813-247-8240.